The destination host will be eta.pha.jhu.edu (you can change that to any other hostname). To see the other default arguments used (such as compression mode), view the HTML source for this page (look under Internet Explorer's View menu).
When the applet pops up it will ask you a series of security questions. These let you choose to restrict the things that the applet can do in order to protect your computer. If you don't trust it to be safe, do not grant it permission to modify files. This will allow you to use it, but you will not be able to use some features, such as saving or retrieving preferences, or verifying the identity of previously used remote computers via host keys.
MindTerm is a signed Java applet from http://www.appgate.org/products/mindterm/. It supports SSH1 and SSH2 client access, as well as both scp and sftp file transfer methods.
This web page is only for use with Internet Explorer browsers version greater than 4.0, on all platforms except the Macintosh. The Java run-time software is too old in both earlier versions of Internet Explorer and in ALL versions of Internet Explorer on the Macintosh (true through at least Internet Explorer 5.0 under MacOS 9.1).